What is the limitation to detect and block Skype?

With DFL-M510-Pattern-3.16, there are two known constraints forblocking Skype:

1. A network administrator sets DF-M510 to block Skypeafter an internal user has logged intoSkype network, and the user never logs off.

2: A user first logs in to Skype network with his/her computerat one place, does not log off, and then connects his/her computerto the network managed by DFL-M510.

Note: by definition, the behavior below iscalled quit Skype network, which is different fromthe behavior of log off Skype.

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